1. Field of Invention
The present invention relates to a semi-transparent reflective electro-optic apparatus, electronic equipment using the same, and a method of manufacturing the semi-transparent reflective electro-optic apparatus. More particularly, the invention relates to an arrangement of pixels in the semi-transparent reflective electro-optic apparatus.
2. Description of Related Art
The related art includes an electro-optic apparatus, such as a liquid crystal apparatus, which is usable as a direct-view-type display for various types of equipment. Of all the types of electro-optic apparatus, for example, in an active matrix liquid crystal apparatus using a TFT as a non-linear pixel-switching element, as shown in FIG. 11 and FIG. 12, a TFT array substrate 10 and a counter substrate 20 sandwich liquid crystals 50 used as an electro-optic material. The TFT array substrate 10 is provided with a pixel-switching TFT (Thin Film Transistor) 30, and a pixel electrode 9a composed of a transparent conductive film, such as an ITO film, and electrically connected to the TFT 30.
In the case of a reflective liquid crystal apparatus, a light-reflecting film 8a, which is used to reflect outside light incident from the counter substrate 20 side toward the counter substrate 20, is formed on the lower layer side of the light-transmitting pixel electrode 9a, so that, as indicated by an arrow LA of FIG. 12, light incident from the counter substrate 20 side is reflected on the TFT array substrate 10 side, and an image is displayed with light coming out from the counter substrate 20 side (reflection mode).
In the reflective liquid crystal apparatus, however, when light reflected on the light-reflecting film 8a has strong light directionality, the dependency on a viewing angle, such as an event that the brightness differs with an angle at which an image is viewed, becomes noticeable. Hence, when a liquid crystal apparatus is fabricated, photosensitive resin, such as acrylic resin, is applied on the surface of an interlayer insulation film 4 or a surface protection film (not shown) formed on the surface thereof, in a thickness of 800 nm to 1500 nm, and a lower layer light-transmitting film 13a of a specific pattern made of the photosensitive resin layer is selectively left through the use of the photolithographic technique, so that a concavo-convex pattern 8g is provided to the surface of the light-reflecting film 8a. If no further treatment is applied, the edge of the lower layer light-transmitting film 13a appears directly on the concavo-convex pattern 8g. Hence, another layer, that is, an upper layer light-transmitting film 7a made of a photosensitive resin layer with high fluidity, is applied and formed atop the lower layer light-transmitting film 13a. The concavo-convex pattern 8g of an edgeless and smooth shape can be thus provided to the surface of the light-reflecting film 8a. For instance, such a concavo-convex pattern is disclosed in JP-A-10-319422.
Of the reflective types of liquid crystal apparatus, in the case of a semi-transparent reflective liquid crystal apparatus capable of display in the transparent mode as well, the light-reflecting film 8a is provided with a light-transmitting window 8d in a region overlapping the pixel electrode 9a on a plane. The region corresponding to the light-transmitting window 8d is of a flat plane, because either the lower layer light-transmitting film 13a is formed across the entire surface or the lower layer light-transmitting film 13a is not formed at all in the region.
In the semi-transparent reflective liquid crystal apparatus arranged in this manner, a backlight device (not shown) is placed on the TFT array substrate 10 side. By allowing light emitted from the backlight device to be incident from the TFT array substrate 10 side, light heading to the light-reflecting film 8a does not contribute to display as it is shielded by the light-reflecting film 8a as indicated by arrows LB1 and LB2 of FIG. 13. However, as indicated by an arrow LB0 of FIG. 12 and FIG. 13, light heading to the light-transmitting window 8d where no light-reflecting film 8a is formed passes through the light-transmitting window 8d toward the counter substrate 20, and thereby contributes to display (transparent mode).
Japanese Patent Application No. 2001-377304 discloses a liquid crystal apparatus arranged in this manner.
With the related art semi-transparent reflective liquid crystal apparatus, however, a quantity of display light in the reflection mode and a quantity of display light in the transparent mode are defined totally by the areas of the light-reflecting film 8a and the light-transmitting window 8d. Hence, there is a problem that when the brightness of display is increased in one mode, the brightness of display in the other mode is sacrificed, and the brightness of display cannot be increased in the both modes.
The invention addresses the above and/or other problems, and provides a semi-transparent reflective electro-optic apparatus capable of increasing a quantity of display light in either of the reflection mode and the transparent mode, and electronic equipment including the same.
In order to address or achieve the above, according to the invention, a semi-transparent reflective electro-optic apparatus is provided including, on a light-transmitting substrate retaining an electro-optic material, a light-transmitting concave and convex forming film which defines specific concave portions and convex portions, and a light-reflecting film formed over the concave and convex forming film, with a light-transmitting window being formed in the light-reflecting film. A back surface of the light-reflecting film includes, in a partial region of a periphery of the light-transmitting window, a light-guiding reflection surface that opposes a surface of the light-reflecting film in a region opposing the partial region with the light-transmitting window in between, so that part of light incident from a back surface side of the light-transmitting substrate is reflected on the light-guiding reflection surface and guided to a surface side of the light-transmitting substrate.
With the semi-transparent reflective electro-optic apparatus to which the invention is applied, display in the reflection mode is possible because the light-reflecting film is formed, and display in the transparent mode is also possible because the light-transmitting window is formed in the light-reflecting film. The back surface of the light-reflecting film includes the light-guiding reflection surface that reflects and guides light incident from the back surface side of the light-transmitting substrate to the surface of the light-reflecting film opposing the light-guiding reflection surface with the light-transmitting window in between. Hence, of the light incident from the back surface side of the light-transmitting substrate on, light that is shielded in the related art by the light-reflecting film and does not contribute to display in the transparent mode is partly reflected on the light-guiding reflection surface and guided to the surface of the light-reflecting film, and thereby contributes to display in the invention. For this reason, a quantity of display light in the transparent mode can be increased without enlarging the area of the light-transmitting window. It is thus possible to enhance the brightness of display in the transparent mode without sacrificing the brightness of display in the reflection mode.
According to the invention, it is preferable that the concave and convex forming film is composed of a lower layer light-transmitting film formed into a specific pattern, and an upper layer light-transmitting film formed on an upper layer side of the lower layer light-transmitting film. When arranged in this manner, even when the lower layer light-transmitting film has edges, the upper layer light-transmitting film eliminates the edges. It is thus possible to form concave portions and convex portions of an edgeless and smooth shape on the surface of the light-reflecting film.
According to the invention, when the light-guiding reflection surface is formed on the back surface of the light-reflecting film, for example, a frame-shaped protrusion forming a frame-shaped convex portion along an outer rim of the light-transmitting window with respect to a surface of the concave and convex forming film is formed on a lower layer side of the light-reflecting film, and the light-guiding reflection surface is formed of a back surface of the light-reflecting film covering the frame-shaped convex portion from a foot portion to a top portion on a side opposite to a side where the light-transmitting window is formed. Also, a surface of the light-reflecting film opposes the light-guiding reflection surface and forms a reflection surface to which light reflected on the light-guiding reflection surface is guided, by covering the frame-shaped convex portion with the light-reflecting film from a foot portion to a top portion on a side where the light-transmitting window is formed, at a portion opposing the light-guiding reflection surface with the light-transmitting window in between.
According to the invention, it is preferable that the reflection surface for light reflected on the light-guiding reflection surface opposes the light-guiding reflection surface as a parallel or nearly parallel plane.
According to the invention, it is preferable that the frame-shaped protrusion is composed of a light-transmitting film formed in a same layer as the lower layer light-transmitting film.
In this case, it is preferable that the frame-shaped protrusion and the lower layer light-transmitting film are formed with rounded top surface portions. When arranged in this manner, a light scattering property on the surface of the light-reflecting film can be enhanced. Meanwhile, a portion functioning as the light-guiding reflection surface on the back surface of the light-reflecting film, and the surface portion of the light-reflecting film to which light is guided from the light-guiding reflection surface need to shape slopes. By providing roundness to the top surface of the frame-shaped protrusion, the area of a flat portion that cannot be utilized as the light-guiding reflection surface can be diminished on the back and main surfaces of the light-reflecting film formed on the main surface side of the frame-shaped protrusion, which makes it possible to broaden the portion functioning as the light-guiding reflection surface on the back surface of the light-reflecting film and the surface portion of the light-reflecting film to which light is guided from the light-guiding reflection surface. Accordingly, a light utilization factor in the transparent mode can be enhanced. The phrase xe2x80x9cwith the rounded top surface portionsxe2x80x9d means any shape including a shape such that the entire top surface is made of a curved surface like a hanging bell and a shape such that part of the top surface is left as a flat plane like a bowl, as long as a portion corresponding to the boundary between the top surface portion and the side surface has a curved surface.
According to the invention, it is preferable that the light-reflecting film has a film thickness less than a height of the frame-shaped convex portion. When arranged in this manner, a portion opposing the light-guiding reflection surface via the light-transmitting window can be positioned lower when viewed from the light-guiding reflection surface of the light-reflecting film.
According to the invention, it is preferable that the light-reflecting film is provided with more than one light-transmitting window. When arranged in this manner, under a condition that the area of the light-transmitting window is same, then the light-guiding reflection surfaces can be formed extensively in a case where plurality of small light-transmitting windows are formed in comparison with a case where a single large light-transmitting window is formed. Hence, a light utilization factor in the transparent mode can be enhanced.
According to the invention, a planar shape of the light-transmitting window is, for example, a polygonal having a side parallel or nearly parallel to a side on which the light-guiding reflection surface is formed. When arranged in this manner, because the light-guiding reflection surface and a portion opposing the light-guiding reflection surface through the light-transmitting window of the light reflecting film can be formed efficiently, a light utilization factor in the transparent mode can be enhanced.
According to the invention, the electro-optic material is, for example, a liquid crystal.
The electro-optic apparatus to which the invention is applied can be used as a display apparatus of electronic equipment, such as a mobile computer and a cellular phone.